Data centers route massive quantities of data. Currently, data centers may have a throughput of 5-7 terabytes per second, which is expected to drastically increase in the future. Data centers contain of huge numbers of racks of servers, racks of storage devices and other racks, all of which are interconnected via a massive centralized packet switching resource. In data centers, electrical packet switches are used to route all data packets, irrespective of packet properties, in these data centers.
The racks of servers, storage, and input-output functions contain top of rack (TOR) packet switches which combine packet streams from their associated servers and/or other peripherals into a lesser number of very high speed streams per TOR switch routed to the electrical packet switching core switch resource. The TOR switches receive the returning switched streams from that resource and distribute them to servers within their rack. There may be 4×40 Gb/s streams from each TOR switch to the core switching resource, and the same number of return streams. There may be one TOR switch per rack, with hundreds to tens of thousands of racks, and hence hundreds to tens of thousands of TOR switches in a data center. There has been a massive growth in data center capabilities, leading to massive electronic packet switching structures.
These electronic switching structures are problematic to design, consume large amounts of power, and have limited throughput. Photonic switching consumes less power and has a high throughput with different capabilities and different architectures.